An American U.N. worker abducted more than two months ago headed home Sunday, a day after he turned up unharmed alongside a road in western Pakistan with his hands and feet bound and pleading "Help me, help me."

John Solecki was discovered Saturday evening abandoned in a village some 30 miles south of Quetta near the Afghan border after his captors called a local news agency to tell them where to look, officials said. At one point, the kidnappers had threatened to behead him.

Mohammed Anwar, the owner of a restaurant alongside the main Quetta-Karachi highway, told The Associated Press that he found a bound Solecki lying in the dirt near a wall. Anwar said he heard a voice in the gloom saying "Help me, help me" in English.

Solecki, who headed the U.N. refugee agency's operations in Quetta, made no public comment. Police and U.N. officials declined to discuss what led to his release.

U.N. spokeswoman Jennifer Pagonis said Solecki left the country on a special medical flight early Sunday morning after spending the night in a military hospital in Quetta.

"He seemed OK this morning," Pagonis said, adding that he was looking forward to being reunited with his family. She declined to offer further details.

Interior Minister Rehman Malik said Solecki would fly to Bagram Airfield in Afghanistan and then continue on to the United States.

Malik said the U.N. worker was released after Pakistani President Asif Ali Zardari formed a task force that worked with the top official in Baluchistan, where Quetta is the capital, to convince the kidnappers to free Solecki.

The release was a rare piece of good news amid intensifying violence here that has raised international alarm over the nuclear-armed country's stability. On Saturday, a suicide bomber attacked a paramilitary base in the capital, killing eight.

Solecki's abduction and the killing of his driver on Feb. 2 in Quetta raised concern that he was another victim in a spate of attacks on foreigners blamed on Islamist militants operating from strongholds along the Afghan frontier.

A previously unknown group, the Baluchistan Liberation United Front, had claimed responsibility for the abduction, threatening to behead him and issuing a grainy video on Feb. 13 of a blindfolded Solecki pleading for help.

But the group's name and demands indicated they were ethnic Baluch separatists who have been waging a long low-level insurgency in the impoverished but oil-rich southwest of Pakistan and have no record of taking or killing Western hostages.

The kidnappers had demanded the release of hundreds of people from alleged detention by Pakistani security agencies.

Zardari last week announced that the government had "traced" 200 people previously listed as missing and provincial leaders insist they are no longer holding any political prisoners.

U.N. Secretary-General Ban Ki-moon said he was grateful for the efforts to secure Solecki's release, citing Zardari and Afghan President Hamid Karzai. But Ban, who was in Paris, also pleaded for the release of another U.N. official, Robert Fowler, was still missing in Niger.

Kidnappers in December took Fowler, a Canadian diplomat who serves as Ban's special envoy for Niger, an aide and their driver. The driver was released unharmed almost two weeks ago.

Antonio Guterres, Ban's high commissioner for refugees, expressed relief and gratitude.

The suicide bomber who attacked the base Saturday in Islamabad sneaked in after dark from a wooded area at the rear and detonated his explosives inside one of several large tents used as sleeping quarters.

Another four members of the paramilitary Frontier Constabulary, many of whose members are assigned to guard foreign embassies and VIPs in the city, were wounded, senior police official Bin Yamin said.

The blast was the second in Islamabad in two weeks and follows a militant assault on a police academy in the eastern city of Lahore.

There was no claim of responsibility for Saturday's attack on the police base. However, the leader of a Taliban faction accused of ties to Al Qaeda warned Wednesday that militants would strike soon in Islamabad.

U.S. special representative Richard Holbrooke is due in Islamabad this week to discuss Washington's offer of more assistance — and call for more resolute action against militants on Pakistani territory — under a plan to turn around its stalemated Afghan war effort.

However, U.S. officials have already made clear that they will take action on their own in an area that President Barack Obama last month described as the "the most dangerous place in the world" and almost certainly the hiding place of Al Qaeda chief Usama bin Laden.

On Saturday, a suspected U.S. missile strike on an alleged militant hide-out in Pakistan's North Waziristan tribal region left 13 people dead, Pakistani intelligence officials said.

The dead and injured in Data Khel village included local and foreign militants, but women and children were also killed, said the officials, who spoke on condition of anonymity because they were not authorized to talk to the media.

Pakistan says the strikes violate the country's sovereignty, kill innocent civilians and generate sympathy for the militants. But the U.S. argues that the attacks are an effective tool that has killed a string of militant leaders.